Method and apparatus for automatic language switching for an imaging device

ABSTRACT

Recognizing a language format of an input data stream including reading a next data sample of the input data stream in a current state, selecting a next state in response to the next data sample, transitioning to the next state and repeatedly reading the next data sample and selecting the next state until the next state is an end state, and identifying the language format in response to the current state when the next state is an end state.

BACKGROUND

This disclosure relates to imaging devices, in particular, to automaticlanguage switching in imaging devices.

Some imaging devices may only support a single language format. Forexample a printer may only support a raster data format that is specificto the printer's printing engine. In such a device, the imaging data issent without prior checking to the print data interpreter. If the inputis in the correct language format, the input is recognized and the jobis output; otherwise, some or all of the input is not recognized and thejob is not output, or outputted incorrectly.

Other imaging devices may support multiple language formats. However, anexplicit language switch that precedes the imaging data may be required.A command or other data may be received by the imaging device thatincludes a known or predetermined format specifying the language formatof the subsequent imaging data. For example, many imaging devicessupport explicit language switching by supporting Hewlett Packard'sprinter job language (PJL) command @PJL ENTER LANGUAGE=<language>. Ifthe specified language is supported by the device, the imaging data isthen processed by the corresponding interpreter; otherwise, the input isrejected and the job is not output.

Unfortunately, generators of imaging data that do not use an explicitlanguage switch may not be compatible with imaging devices that requireexplicit language switching.

Alternatively, when an imaging device receives the imaging data withoutan explicit indication of the language format, the imaging device mustsample the imaging data to determine the language format. This processis commonly referred to as automatic language switching.

In one method of automatic language switching, an initial byte sample ofthe input stream of the imaging data is pre-read and passed to alanguage recognition process. For each supported language, there is alanguage specific recognition test, such as looking for a specialsignature in the byte sample. The method applies each language specificrecognition test in a predetermined sequential order until one testacknowledges recognition of the language format. (If none do, an erroris generated.) When the language is recognized, the input stream is thenprocessed by the corresponding language interpreter.

Unfortunately, with each set of imaging data, the recognition tests areperformed in the same order. Thus, for a given language format with arecognition test at the end of the list, every preceding recognitiontest must be performed each time imaging data in that language format isreceived, wasting time and resources.

In another method, an initial byte sample of the imaging data ispre-read and compared against a group of language recognizers with onelanguage recognizer per supported language. Each language recognizergenerates a probability that the language of the imaging data is theassociated language format. The language format with the highestprobability is used.

Unfortunately, by using probabilities to select a language, the resultis only a guess of the correct language, not a specific determination,and may be an incorrect selection. Furthermore, the test for eachlanguage must be performed to determine its associated probability.

In another method, an initial byte sample of the input stream ispre-read and passed to a language recognition process. The languagerecognition process uses a dynamically determined sequential order oflanguage recognizers. The order of language recognizers is updated inresponse to how often the associated language format is found.

Unfortunately, each language recognizer reapplies its entire signaturetest. Thus, even if two language formats have identical initial portionsof their respective signatures, a test for the identical portion may beperformed multiple times.

Accordingly, there remains a need for an improved method and apparatusfor determining a language format of data.

SUMMARY

An embodiment recognizes a language format of an input data stream byreading a next data sample of the input data stream in a current state,selecting a next state in response to the next data sample,transitioning to the next state and repeatedly reading the next datasample and selecting the next state until the next state is an endstate, and identifying the language format in response to the currentstate when the next state is an end state

Another embodiment recognizes a language format of an input data streamby reading a data sample of the input data stream, updating a set ofpotential language formats in response to the data sample, repeating thereading and updating until one or zero potential language formats remainin the set, and if one potential language format remains in the set:verifying that a language format signature for the remaining potentiallanguage format exists in the input data stream, and identifying thelanguage format in response to the verification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a system for automatic languageswitching according to an embodiment.

FIG. 2 is a state diagram illustrating how a language format of an inputdata stream is recognized according to another embodiment.

FIG. 3 is a diagram showing an input data stream and language signaturefragments.

FIG. 4 is a flowchart showing how a language format of an input datastream is recognized according to an embodiment.

FIG. 5 is a flowchart showing how a language format is identified inFIG. 4.

FIG. 6 is flowchart showing how matching language formats are trackedaccording to another embodiment.

FIG. 7 is flowchart showing how preceding data blocks are identified andskipped according to another embodiment.

FIG. 8 is flowchart showing how a language format is recognizedaccording to another embodiment.

FIG. 9 is an example illustrating how a set of potential languageformats is changed.

FIG. 10 is flowchart showing how a set of potential language formats isupdated in FIG. 8.

DETAILED DESCRIPTION

Embodiments identify a language format using data samples from an inputdata stream. As used in this discussion, an input data stream includesany data in any medium that is accessible. For example, an input datastream may be data read from a file on a hard disk device or removablestorage, data stored in a memory, data received through a network orlocal interface, or the like.

A data sample is a portion of an input data stream. The data sample mayhave any size as desired. In one example, the size of the next datasample may be one byte. Alternatively, the size may be the size that aprocessor implementing the method is capable of using in a singlecomparison. For example, a processor may make a comparison between twofour-byte data samples using one machine instruction. Thus, the datasample may have a size of four bytes. Furthermore, the size of the datasample may be selected and varied as desired.

A language format is a particular format of organization orrepresentation of data. A language format may be identified by alanguage format signature. Such a language format signature may be asequence of data samples that identifies an associated language formatfrom among other language formats.

A language signature fragment is a representation of a portion of alanguage format signature. For example, the language format signature of“% PDF” identifies the Portable Document Format (PDF). Any portion ofthe signature may be a language fragment. Thus, “%” and “P” charactersmay be language signature fragments. In addition, larger portions, suchas “DF”, may be language signature fragments. Furthermore, anycombination of portions of a language signature may form a languagesignature fragment.

FIG. 1 is a block diagram showing a system for automatic languageswitching according to an embodiment. The system includes a computerdevice 110. The computer device 110 includes a data sample basedlanguage switching system 140.

In addition, the computer device 110 includes system bus 112, which maybe configured to connect various components and enable data to beexchanged between two or more components. Through the system bus 112,the language switching system 140 may receive data samples in order toidentify a language format of an input data stream. The system bus 112may include one or more of a variety of bus structures including amemory bus or memory controller, a peripheral bus, or a local bus thatuses any of a variety of bus architectures. Additional components thatmay be connected by system bus 112 include processing system 114 andmemory 116. Other components may include one or more mass storage deviceinterfaces 118, input interfaces 120, output interfaces 122, and/ornetwork interfaces 124, each of which will be discussed below.Furthermore, each component may be coupled to one or more of thevarieties of bus structures of the system bus 112; however, eachcomponent may, but need not be coupled to every variety of bus structureof the system bus 112.

The processing system 114 includes one or more processors. For example,the processing system 114 may include a central processor and optionallyone or more other processors designed to perform a particular functionor task. The language switching system 140 may be implemented with theprocessing system 114. Alternatively, the language switching system 140may be independent of the processing system 114.

Typically, the processing system 114 executes the instructions such ascode or data 105 provided on computer readable media, such as on memory116, a mass storage device 126, such as a magnetic hard disk, aremovable magnetic disk, a magnetic cassette, an optical disk, or from acommunication connection, such as the network interface 124, which mayalso be viewed as a computer readable medium.

Memory 116 includes one or more computer readable media. The memory 116may include or be configured to include code or data 105 for thelanguage switching system 140. In addition, such code and data 105 maybe accessed by processing system 114 through system bus 112. Memory 116may include, for example, ROM 128, used to permanently storeinformation, and/or RAM 130, used to temporarily store information. ROM128 may include a basic input/output system (“BIOS”) having one or moreroutines that are used to establish communication, such as duringstart-up of computer device 110. RAM 130 may include one or more programmodules, such as one or more operating systems, application programs,and/or program data.

One or more mass storage device interfaces 118 may be used to connectone or more mass storage devices 126 to system bus 112. Such massstorage devices 126 may contain the data stream to be sampled by thelanguage switching system 140. The mass storage devices 126 may beincorporated into or may be peripheral to computer device 110 and allowcomputer device 110 to retain large amounts of data. Optionally, one ormore of the mass storage devices 126 may be removable from computerdevice 110. Examples of mass storage devices include hard disk drives,magnetic disk drives, tape drives and optical disk drives. A massstorage device 126 may read from and/or write to a magnetic hard disk, aremovable magnetic disk, a magnetic cassette, an optical disk, oranother computer readable medium. Mass storage devices 126 and theircorresponding computer readable media provide nonvolatile storage ofdata and/or executable instructions that may include one or more programmodules such as an operating system, one or more application programs,other program modules, or program data.

The language switching system 140 may receive the data stream through avariety of interfaces. Such interfaces include the input interfaces 120,the output interfaces 122, and the network interfaces 124.

One or more input interfaces 120 may be employed to enable a user toenter data and/or instructions to computer device 110 through one ormore corresponding input devices 132. Examples of such input devicesinclude a keyboard and alternate input devices, such as a mouse,trackball, light pen, stylus, or other pointing device, a microphone, ajoystick, a game pad, a satellite dish, a scanner, a camcorder, adigital camera, and the like. Similarly, examples of input interfaces120 that may be used to connect the input devices 132 to the system bus112 include a serial port, a parallel port, a game port, a universalserial bus (“USB”), a firewire port (IEEE 1394), or the like.

One or more output interfaces 122 may be employed to connect one or morecorresponding output devices 134 to system bus 112. Examples of outputdevices include a monitor or display screen, a speaker, a printer, andthe like. A particular output device 134 may be integrated with orperipheral to computer device 110. Examples of output interfaces includea video adapter, an audio adapter, a parallel port, a USB, a firewireport, or the like.

One or more network interfaces 124 enable computer device 110 toexchange information with one or more other local or remote computerdevices, illustrated as computer devices 136, via a network 138 that mayinclude hardwired and/or wireless links. Examples of network interfacesinclude a network adapter for connection to a local area network (“LAN”)or a modem, wireless link, or other adapter for connection to a widearea network (“WAN”), such as the Internet. The network interface 124may be incorporated with or peripheral to computer device 110. In anetworked system, accessible program modules or portions thereof may bestored in a remote memory storage device. Furthermore, in a networkedsystem computer device 110 may participate in a distributed computingenvironment, where functions or tasks are performed by a plurality ofnetworked computer devices. In addition, the network interfaces 124 mayallow connection to additional input devices 123 and/or output devices134 that may communicate through a network interface 124. Suchadditional input devices 123 and/or output devices 134 may be integratedwith or peripheral to the computer device 110.

FIG. 2 is a state diagram illustrating how a language format of an inputdata stream is recognized according to an embodiment. Table 1 listsexamples of byte sequences that correspond to language formats. Table 2is a list of byte sequences that are used in the state diagram of FIG.2. Where a “\” is followed by three numbers, the three numbers are anoctal representation of a byte. Note that one of the TIFF byte sequencesof Table 2 has been modified from II*<NUL> to MM*<NUL> for illustrationpurposes.

TABLE 1 Byte Sequences Identifying Language Formats Language ByteSequence PJL @PJL Postscript %!PS PDF %PDF PCL <Esc>E PCL XL ) HP-PCLXL; TIFF II*<NUL> or MM<NUL>* JPEG \377\330 JP2K \377\117 PNG \211PNG

TABLE 2 Sample Byte Sequences for Illustration Language Byte SequencePostscript %!PS PDF %PDF TIFF MM*<NUL> or MM<NUL>*

The key 69 of FIG. 2 illustrates attributes of most states. A state 70has next state transitions 76 and a default transition 78 defined forit. The next state transition 76 illustrates a match of a data samplewith potential language formats associated with the state. There may bemultiple next state transitions 76. In addition, such a next statetransition 76 need not be present. If such a next state transition 76 ispresent, and there is a match with the data sample and the languagesignature fragment associated with the next state transition 76, thenext state 72 may be selected to be the next state.

Each state 70 has a default transition 78. Even if the state 70 has nonext state transitions 76, the state 70 will have a default transition78. The default transition 78 transitions to an end state 74. Forclarity, the states in FIG. 2 do not have the respective defaulttransitions 78 and end states 74 illustrated.

As can be seen in the state diagram of FIG. 2, a next state transition76 is associated with a language signature fragment. For example, thelanguage signature fragments associated with next state transitions 76from the “%” state 94 include a language signature fragment of “!” and alanguage signature fragment of “P”. Although such language signaturefragments may be represented by a single byte, other sizes or encodingsmay be used. For example, a Unicode Transformation Format (UTF) encodedcharacters may include multiple bytes for a single character.

FIG. 3 is a diagram showing an input data stream and language signaturefragments. Bytes 150 are bytes of the input data stream. In thisexample, the bytes 150 are in a sequential order. Language signaturefragments 152, 154, and 156 are part of the input data stream. Asdescribed above, a language signature fragment may have a variety ofsizes. In this example, language signature fragments 152 and 154 eachhave a size of one byte. In contrast, language signature fragment 156has a size of two bytes.

The states may be represented in a variety of ways. In one example, anarray of 256 pointers may be maintained with one pointer for eachpossible value of a byte. Each value in the array may be a pointer to alist of possible next states of matching language formats. Thus, thebyte is used as an index to the array to determine the next state.

In another example, a state may include an enumerator of a list of bytevalues. Each byte value has an associated pointer to a list of possiblenext states. In addition each byte value may be associated with amatching language format. With such a state, each possible byte may, butneed not be included in the list. For example, only byte valuesassociated with matching language formats or additional states may beincluded in the list.

Furthermore, one state format need not be used for every availablestate. For example, an initial state may be in the format of an arraywith an element for each possible data sample. The first data sample maybe compared against bytes in the list. If there are none, then thelanguage format is non-determinative. Subsequent states may berepresented by a list of byte values associated with matching languageformats and potential next states. Data samples are compared with thelist of bytes to determine if there is a next state.

FIG. 4 is a flowchart showing how a language format of an input datastream is recognized according to an embodiment. Referring to FIGS. 2and 4, a current state begins in the Initial State 90. A next datasample of the input data stream is read in 10. A next state is selectedin 12 in response to the next data sample.

Using the state diagram of FIG. 2, an example of the selection of a nextstate in 12 will be illustrated. From the initial state 90, a datasample is compared with the state transitions of that state. For theinitial state 90, there are two transitions corresponding to languagesignature fragments “M” and “%”. For example, if the language signaturefragment “M” matches the data sample, the next state is the “M” state92. Similarly, if the language signature fragment “%” matches the datasample, the next state is the “%” state 94. If the data sample does notmatch either the “M” or the “%” language signature fragments, the nextstate is the end state.

If the next state is not an end state in 14, the current statetransitions to the next state in 16 as indicated by the data sample.Alternatively, if the next state is the end state, the language formatis identified in 18.

As described above, the size of the data sample may be selected asdesired. Furthermore, the data sample may be of a fixed size or avarying size. In one example, the selection of the data sample is madeto minimize possible state transitions. Referring to FIG. 2, a one bytedata sample size may be used during the transitions from the “%” state94 to either the “% !” state 98 or the “% P” state 100. However, boththe “% !” state 98 and the “% P” state 100 include two sequentialtransitions to reach a state including a matching language format. Thus,for the transitions from either state, the data sample size read in 10may be changed to two bytes and be compared to a corresponding two bytelanguage signature fragment. For example, if the current state is the “%P” state 100, a two byte next data sample may be compared with the twobyte language signature fragment of “DF”. As a result, only onetransition to the “% PDF” state 95 is made, where two state transitionswould have been made had a one byte data sample been used.

In one example of identifying the language format in 18, the languageformat is identified based on the current state before the end state. Ifa state having a match is the current state, then the language formatassociated with the match is determined to be the language format. Forexample, consider the input data stream having the sequence “% PDF”. Thestate transitions would eventually result in the current state being the“% PDF” state 97, with a match to the PDF language format. Since thatstate has no transitions other than the end state, the match to the PDFlanguage format associated with that state is used as the languageformat.

Alternatively, consider the input data stream having the sequence “%PDX”. Thus, the state transitions would lead to the “% PD” state 108.However, the data sample of“X” would not match a language signaturefragment associated with a transition out of the “% PD” state. Thus, theend state would be the next state. The “% PD” state 108 does not have amatching language format. As a result, the language format is identifiedas non-deterministic in 18.

Thus, using an embodiment described above, a first byte is compared withthe first bytes of the known language format signatures. Subsequentbytes are compared with corresponding bytes of known language signaturesthat have matched the prior bytes. If at any point, there is no matchwith a current byte, there is either a language format identified or thelanguage format is non-deterministic.

Although in FIG. 2 only states with no further transitions areillustrated as having matches, a particular state may include both amatching language format and transitions to other states for additionalmatching language formats. However, the matching language format may beidentified as the language format even if there may be more potentialmatches. Accordingly, even though additional transitions may bepossible, the next state is indicated as the end state. Since there is amatch associated with the current state, the matching language format isidentified as the language format.

A next data sample may be an initial sample if no data samples have beenread. Furthermore, a next data sample may include an inherent sequence.For example, the next data sample may be the next byte of the input datastream, selected in a sequential order. However, the next data sampleneed not be the next sequential data sample.

The reading of the next data sample in 10 may be implemented in avariety of ways. For example, reading may include access to a bufferstoring a portion of the input data stream. Alternatively, reading maybe a process requesting data from a pre-read process reading the inputdata stream. As described above, the next data sample may have any sizeas desired. In addition, the size of the next data sample may bedifferent from reading to reading. Furthermore, although a desired datasample size may be a byte, word, or other common size, the data readfrom the input stream may be in a larger block as desired. For example,it may be more efficient to read data from the input stream in 512 byteblocks. Readings of the data sample in 10 may be made from a bufferstoring the 512 byte block.

A pre-reading process may initiate the method for determining thelanguage format. Specifically, the pre-reading process may initiate thereading of the data samples. Alternatively, the reading of the datasamples may be a currently running process that requests data from apre-read process. As additional data samples are read, requests may bemade to the pre-reading process for additional data following the mostrecently read data sample.

In another embodiment, after transitioning to the next state in 16, itis determined if the current state indicates a matching language formatin 11. If there is a matching language format, the matching languageformat is identified as the language format in 18. Thus, a matchinglanguage format may be found, yet the current state may indicate thatthere are additional possible matches through additional potential nextstates. That matching language format is identified as the languageformat in 18.

Operation 11 in FIG. 3 is illustrated using dashed lines. Such dashedlines, and similar dashed lines used in other figures represent optionaloperations that may be included in various other embodiments orcombinations of embodiments.

Alternatively, even if there is a matching language format, a next datasample may be read to compare to next possible states. As the statemachine progresses, further data samples may be read. However, anothermatching language format may not be found. In such a case, theadditional data samples that were read after the first matching languageformat was found may in fact be part of the data formatted in the firstmatching language format. Thus, the additional data samples read todetermine if there were any other matching language formats may bepushed back to be processed with the rest of the data associated withthe language format. As a result, those data samples would be availablefor interpretation of the data in the matching language format.

FIG. 5 is a flowchart showing how a language format is identified inFIG. 4. In 20, a most recent state is determined. The most recent stateis selected from among the current state and previous states thatinclude a matching language format. As described above, the currentstate may have a corresponding language format match. If so, the currentstate would be determined as the most recent state. Thus, in 22, thematching language format of the current state would be selected as thelanguage format.

Alternatively, previous states may be examined to determine if there wasa previous matching language format. For example, consider two languageformats with one having a signature that is equivalent to a firstportion of the signature of the second format. A match will be made whenthe state machine detects the signature of the first language format.However, because the second language format signature includes theentire first language format signature, such a match is still notdeterminative. Thus, a tentative match is indicated and the statemachine proceeds to attempt to match the second language formatsignature.

If a match is made with the second language format, then that languageformat may be selected. However, if a match is not made, then the statemachine returns to the most recent state where there was a match, inthis case, the match with the first language format signature. Sincethat state is the most recent state with a match, that matching languageformat is selected as the language format.

However, if no most recent state with a match is found, the languageformat is determined to be non-deterministic. In such a case, no currentor previous state resulted in a matching language format.

FIG. 6 is flowchart showing how matching language formats are trackedaccording to another embodiment. In 28, any matching language format ofthe current state is tracked. Thus, when the next state is an end statein 14, the most recent matching language format may be selected in 30.Such a selection in 30 may be made without interrogating previous statesas described above.

The tracking of matching language formats may be performed in a varietyof ways. For example, any matched language format may be placed on astack. Thus, if multiple matching language formats are found, the mostrecently placed matching language format on the stack may be selected asthe matching language format.

Alternatively, a matched language format pointer may be modified when astate having a matching language format is reached. The pointer may beinitialized to indicate a non-deterministic match. Then, each time astate includes a matching language format, the pointer is updated. Afterreaching an end state, the pointer indicates the matching languageformat. If no matching language formats were found, then the pointerindicates that the language format is non-deterministic. Any suchtechnique for tracking a matching language format may be used in 28

Referring to FIG. 4, after a language format is determined, a callbackassociated with the language format may be executed in 32. Within aparticular language format, there may be language format specific data.Such data may include indications of the language format version,encodings used within the data stream, or other format specific data.Such encodings may include encryption formats, compression formats, orother encodings of the data. This information may be made available toany process requesting such information. A callback function specific tothe language format may be executed in 32 to read and interpret suchlanguage format specific data. To enable the execution of such acallback function in 32, a pointer to the callback function may bereturned by the language determination process.

After a language format is identified in 18, the input data stream maybe rendered in 19 as desired. With knowledge of the language format, thedata may be rendered according to the language format. Rendering may beany presentation of the data. For example, printing of the data may berendering. In addition, converting the data into another format may berendering. Such conversion may include adding additional data such asprocessing commands or device specific commands suitable for a targetimaging device. For example a device implementing an embodimentdescribed above may be a front end for a legacy imaging device incapableof rendering prevailing image formats. The device may process the inputdata stream into a format acceptable by the legacy imaging device andinclude appropriate commands to control the legacy device.

As described above, data samples are read and compared with languagesignatures. However, if no more data samples are available, even thoughthe state machine has not reached an end state, the state machine mayindicate that the language is non-deterministic.

The data stream may include processing additional data within the inputdata stream. For example, the input data stream may have preceding datasuch as escape sequences, specific commands, or other metadata precedingthe image data. Referring to FIG. 4, to aid in determining the languageformat, such preceding data may be isolated in 34 from the input datastream. Such preceding data may be isolated in 34 in a variety of ways.

FIG. 7 is flowchart showing how preceding data blocks are identified andskipped according to another embodiment. In 36, the format of apreceding data block is identified. In 38, the preceding data block isskipped.

For example, tests may be performed for known formats of the precedingdata. For example, a Universal Exit Language (UEL) sequence may includean escape character (such a hexadecimal value of 0x1B) followed by aparticular byte sequence (such as %-12345X). The process may check thedata sample for the escape character. If found, the process may read abyte sample of the expected additional bytes to confirm the UEL. If sucha UEL is found, it may be recorded for later use. The UEL may bestripped from the data stream.

Some preceding data may have a variable length. In particular, markuplanguage formats, such as the Extensible Markup Language (XML), includetags that delineate elements. For example, an opening “<body>” tag mustbe eventually followed by a closing “</body>” tag. However, the lengthof intervening data may not be determinable from the opening tag. Byidentifying the particular format in 36, data between the opening tagand the closing tag may be skipped in 38. In this example, any databefore and including a closing “</body>” tag would be skipped.

Although XML has been used as an example, other formats may have varyingdata lengths between tags or other identifiers. Such formats may havecorresponding terminators indicating the end of that particular datablock. The identification of the format in 36 allows skipping thepreceding data block by searching for the appropriate terminatorassociated with the format.

After such preceding data is isolated from the data stream, the statemachine described above may proceed to identify the language format.

If at some point, there is a failure to recognize a format of expectedpreceding data, the flow may return any read bytes used in attempting todetermine the format of the preceding data to the reading process. Thus,any data that was not recognized maybe subsequently used in otherinstances of a state machine, for example, a state machine to recognizethe language format of the input data stream as described above.

Similar to determining the language format of the input data stream, asimilar state machine may be used to process the preceding data. Similarto the language format, the identity or format of preceding data may notbe known. By using such a state machine and comparing the read datasamples to the signatures of the preceding data formats, the format ofthe preceding data may be discovered. Thus, the preceding data may beprocessed accordingly.

Regardless of the method used to isolate the preceding data, anypreceding data may be indicated for later processing. Such indicatingfor later processing may include storing the preceding data, referencingthe preceding data, setting a flag associated with the preceding data,or the like. For example, a PJL command may change the paper size for anassociated print job. After the language format is recognized, the PJLcommand may be processed appropriately in 39. However, if the languageformat of the input data stream is not recognized, the PJL command neednot be applied to the imaging device.

Referring to FIG. 7, a callback function associated with the identifiedformat of a preceding data block may be executed in 40. As describedabove, the language formats may have associated callback functions.Similarly, the preceding data format may have an associated callbackfunction. For example, as described above, if an XML tag is found, acallback may be executed to search for the corresponding closing tag.Thus, the callback function may be relied upon to return a location inthe data stream beyond the XML data, such that the XML data is skipped.Thus, the execution of the callback function in 40 may be a replacementfor skipping the preceding data in 38. In addition, the callbackfunction may process the associated preceding data appropriately.

As described above, identifying the preceding data may be performedusing a state machine described above in reference to the languageformats. In addition, the same state machine may be used for bothprocessing the preceding data and identifying the language format. Forexample, both the language format of data within the input data streamand the preceding data may have identifiable signatures. Thus, the statemachine analyzes the input data stream until a matching signature isfound.

Once a signature is found, the appropriate callback function may beexecuted. Such callback functions would appropriately process the data.For example, a callback for a block of preceding data including setupcommands for an imaging device may issue the commands to the imagingdevice. A callback for an identified language format may render the datato the imaging device appropriately. Thus, each block of data,regardless of type or format, would be processed appropriately aftermatching the signature. After processing, the callback function mayreturn processing to the state machine with a current position of theinput data stream after the preceding data block.

Another embodiment includes verifying requirements associated with thepreceding data block in 42 and indicating an error if the requirementsare not satisfied in 43. Some formats of preceding data haveprerequisites or requirements. For example, a PJL command should bepreceded by a UEL byte sequence. If the UEL byte sequence does notappear in the data stream, then a requirement of the PJL command is notverified in 42. Thus, in 43, an error is indicated.

FIG. 8 is flowchart showing how a language format is recognizedaccording to another embodiment. In 50, a data sample of the inputstream is read. In 52, a set of potential language formats is updated inresponse to the data sample. In 54, it is determined whether one or zeropotential language formats remain in the set. If there are more than onepotential language formats in the set, another data sample is read in 50to narrow down the remaining potential language formats. Thus, inresponse to the data samples, the set of potential language formats isreduced to one or zero.

If zero language formats remain in the set, all potential languageformats were removed from the set. Thus, the format is indicated asnon-deterministic in 60. If one language format remains, the languageformat signature of that language format is verified in 56. Although theset of potential language formats is reduced to one, the preceding datasamples may not completely match the language format signature of theremaining language format. The verification in 56 checks any additionaldata samples needed to verify the language format signature of theremaining language format.

FIG. 9 is an example illustrating how a set of potential languageformats is changed. Referring to FIG. 8 and FIG. 9, the initial set 80indicates four potential language formats. An initial set 80 may, butneed not include all potential language formats available. Furthermore,the initial set 80 need not be fixed. For example, subsequent updates orrevisions may be made to the set to add or remove language formats toand from the initial set 80.

In this example, the first data sample that is read is a “%” byte. Thus,the arrow 86 illustrates the updating of the initial set 80 in 52 intoan updated set 82. Since there are two remaining potential languageformats in the set, the set is updated again in 52 in response to a datasample of “P”, illustrated by arrow 88.

In the updated set 84, there is only one remaining potential languageformat in the set, “PDF”. However, since only the language signaturefragment “% P” has been matched, the remaining language signaturefragment “DF” must be matched to verify the language format signature in56. The language format may be identified in response to theverification in 58.

In another example, as described above, a first language formatsignature may be wholly contained within a second language formatsignature. Thus, the set may be updated until two potential languageformats remain in the set: the first language format that was matched,and the second language format that has remaining unverified signaturefragments. Updating the set in 52 may include removing a matchedlanguage format from the set if a subsequent matching language format isfound. Thus, in this example, if subsequent data samples indicate amatch with the second language format signature, the first languageformat, which was matched, is removed from the set. Thus, only onelanguage format remains in the set to be verified in 56 and identifiedin 58. Alternatively, if the second language format signature is notfound, then the second language format is removed from the set, leavingthe first language format in the set to be verified in 56 and identifiedin 58.

As described above, once a language format is identified, an associatedcallback function may be executed. In an embodiment illustrated in FIG.8, a matching language format may be identified in 58. Then theassociated callback function may be executed in 62.

Reading the next data sample may include reading the next data sample insequence. For example, bytes may be read in sequence. Referring to FIG.9, first a byte representing a “%” is read, followed by a byterepresenting a “P”. By reading data samples in sequence and updating theset of potential language formats accordingly, a particular byte of thedata stream need only be read once in order to determine a languageformat.

FIG. 10 is flowchart showing how a set of potential language formats isupdated in FIG. 8. In 53, the data sample is compared with correspondinglanguage signature fragments. Potential language formats with matchingsignature fragments are selected in 55 to remain in the set.

The comparison may, but need not be a comparison between the data sampleand every corresponding language signature fragments. For example, onlyone comparison may be made with a language fragment that is common tomultiple potential language formats in the set. As described above, bothPS and PDF formats included a “%” character as a first languagefragment. One comparison is made between the language signature fragment“%” and the data sample to determine if both PS and PDF should remain aspotential language formats. Thus, from the comparison, potentiallanguage formats including language signature fragments matching thedata sample are selected to remain in the set in 55 during the updatingin 52.

Furthermore, any of the above-mentioned methods may be implementedthrough an article of machine-readable code, embodied in amachine-readable medium that, when executed in the machine, causes themachine to perform the method. A machine may be any device or systemcapable of executing code, such as general purpose computers,application specific integrated circuits, programmable logic devices,digital signal processors, or the like. For example, the computer device110 of FIG. 1 may be controlled through firmware, code, or other data105 stored in the memory 116. Although the code and data 105 has beenillustrated in FIG. 1 as being stored in the memory 116, the code anddata 105 may be stored in other storage devices such as the mass storagedevices 126, other computer devices 136 attached through the network138, or the like.

Embodiments embrace one or more computer readable media. Each medium mayinclude or may be configured to include the machine-readable codeincluding data structures, objects, programs, routines, or other programmodules that may be accessed by a processing system, such as oneassociated with a general-purpose computer capable of performing variousdifferent functions or one associated with a special-purpose computercapable of performing a limited number of functions. Themachine-readable code may cause the processing system to perform aparticular function or group of functions.

Furthermore, examples of computer readable media include random-accessmemory (“RAM”), non-volatile random access memory (“NVRAM”), read-onlymemory (“ROM”), programmable read-only memory (“PROM”), erasableprogrammable read-only memory (“EPROM”), electrically erasableprogrammable read-only memory (“EEPROM”), compact disk read-only memory(“CD-ROM”), removable storage (e.g., USB thumb-drive), or any otherdevice or component that is capable of providing data or executableinstructions that may be accessed by a processing system.

In addition, the machine-readable code may include code for a variety ofprocessors or other computing devices that may execute code. Thus, themachine-readable code may include, for example, code such as processorspecific code and programmable logic device configuration data. Thus, adevice may be manufactured that has the capability of identifyinglanguage formats in input data streams as described above, but in whichthe capability is not implemented. However, through a subsequent updateor retrofit, whether software, firmware, or other code, thefunctionality may be enabled in the device.

Additionally, the language format identifier may be implemented as aservice external to the device. For example, the machine-readable codemay be executed on a processor or system external to an imaging device.The identified language format may be communicated to the imaging devicefrom the external system.

Another embodiment includes an apparatus for identifying a languageformat. The above described methods may be implemented in an apparatussuch as the computer device 110 described above. Furthermore, thecomputer device 110 may be a general-purpose or a special-purposecomputer, or a combination of such computers. For example, computerdevice 110 may be a printer, a multi-functional peripheral (“MFP”), ascanner, a facsimile device, an electronic whiteboard, a displaymonitor, a tablet PC, a document server, general purpose computer,special purpose computer, a personal computer, a notebook computer, apersonal digital assistant (“PDA”) or other hand-held device, aworkstation, a minicomputer, a mainframe, a supercomputer, amulti-processor system, a network computer, a processor-based consumerelectronic device, or the like.

Embodiments described above may be used for any process that can performan operation on a variety of input formats. For example, suchembodiments may be used in faxing, scanning, copying, filing,conversion, publishing, or the like.

While embodiments have been described with reference to identifying alanguage format for the purpose of interpreting the data, it may be usedfor any purpose, such as a preprocessing phase prior to interpretation.For example, a preprocessing phase may add a border, logo, banner, orany other additional data. By identifying the language format, theadditional data may be added in the same format.

Although particular processes have been described as parts of particularembodiments of methods, such processes may be combined with otherembodiments as desired.

Although particular embodiments have been described, it will beappreciated that the principles of the invention are not limited tothose embodiments. Variations and modifications may be made withoutdeparting from the principles of the invention as set forth in thefollowing claims.

1. A method of recognizing a language format of an input data stream, comprising: receiving the input data stream in an imaging device; reading a next data sample of the input data stream in a current state, wherein a size of the next data sample is selected in response to at least one of the current state and a next state; selecting the next state in response to the next data sample, comprising: comparing the next data sample with a list of data sample values associated with the current state, each state being associated with only a single list of data sample values and each data sample value of the list associated with a different language signature; and selecting the next state in response to a match between the next data sample and one of the data sample values in the list; transitioning to the next state and repeatedly reading the next data sample and selecting the next state until the next state is an end state; identifying the language format in response to the current state when the next state is an end state; and rendering a remainder of the input data stream according to the identified language format with the imaging device.
 2. The method of claim 1, wherein identifying the language format in response to the current state comprises: determining a most recent state from among the current state and previous states that includes a matching language format; selecting the matching language format from the most recent state as the language format; and indicating that the language format is non-deterministic when no most recent state is found.
 3. The method of claim 1, further comprising: tracking a matching language format when the current state includes the matching language format; and selecting a most recent tracked matching language format as the language format.
 4. The method of claim 1, further comprising: executing a callback function for the identified language format.
 5. The method of claim 1, further comprising: isolating preceding data from the input data stream.
 6. The method of claim 5, further comprising: identifying a format of a preceding data block; and skipping the preceding data block in response to the identified format of the preceding data block.
 7. The method of claim 6, further comprising: executing a callback function associated with the identified format of the preceding data block.
 8. The method of claim 6, further comprising: verifying a presence of data blocks in the input data stream required for processing the preceding data block; and indicating an error if the data blocks are not present.
 9. The method of claim 1, further comprising: identifying a matching language format as the language format when the current state indicates the matching language format.
 10. The method of claim 1, wherein the next data sample has a fixed size.
 11. The method of claim 10, wherein the fixed size is one byte. 